The present invention is related to a system that reads high densely recorded barcodes by using a laser diode array and interfaces with an information system. In detail, said invention is the barcode reading system and the reading method using the laser diode array for realizing postal service automation and logistic sorting automation.
Generally, for the automatic postal matter sort, a postal service platform uses four-state barcode print in 0.001 mm specification, which needs to be read by precise measurement method. Moreover, in a logistics information platform, a {fraction (3/1000)}xcx9c{fraction (6/1000)} inch spot is scanned and read for logistics sorting purposes, which is comprised of one- or two-dimensional barcodes. But, in this case if the barcodes are reduced to less than some extent of scale, i.e., {fraction (1/1000)} mm, a large amount of information could be recorded but it would be impossible to read. Namely, it is possible to decipher the barcodes with the distance between bars at least in the range of 0.076xcx9c0.152 mm. In the case of logistics barcode, because the barcodes are required to be printed repetitively for large quantity products by using the fixed lot number and information of those large quantity lots, a precise system, which accurately measures and verifies printed barcode quality, is required.
As stated above, in logistical purpose barcode as well as postal information barcode, it is very important to develop a system and a method that can examine and verify the quality of barcodes, which are used as a method of information acquisition and can accurately read those barcodes. Especially in the case of the postal information platform, for the fast sorting of postal matters, the print quality of barcode is more important than ever. In the case of the logistics platform, the print quality is again important for reading a large amount of information of the moving barcodes attached on products moving at a high speed.
In other words, a four-state barcode reader, which is used in automatic postal matter sorting, examines and reads the barcode""s accurate print status and is applied to automatic postal sorting system and, contributes improving the postal service productivity. For this purpose, an important aspect is the precise barcode reading capability.
Previous methods for reading barcodes used either a laser beam or an image capturing method. But the laser beam is unable to read small barcodes because its barcode reading standard spot size is as large as 0.7xcx9c0.15 mm unit. And, in case the of image capturing method, if one pixel value is defined as 600 PPI (Pixel Per Inch), its unit is about 0.042 mm, which enables precise barcode reading. But, for reading barcodes in the 600 PPI level, the reading area becomes small and correspondingly, the printed barcode""s position must be changed or it will be impossible to read the long barcodes.
If the laser beam is applied to an automatic postal sorting system, the following problems occur. Namely, according to the moving speed of the spot, which is scanned on moving objects, and of the barcode printed objects (postal matters), an unread area can occur. And, if barcodes are read through scanning the laser beam on fixed reading objects by using a handheld barcode reader, information is acquired by ratio values, which cannot read with less than a 0.001 mm unit accurately.
As mentioned, if the laser beam barcode reading method is applied to the automatic postal sorting system, partially reduced or enlarged barcodes are not able to be sorted. Namely, erroneous postal matters due to the error in reading the bar""s width, space and height are sorted as erroneous postal matters when performing automatic postal sorting, and they need to be sorted by hand.
Moreover, if logistics purpose barcodes are reduced and printed less than a certain size (generally less than {fraction (1/1000)} mm), it is impossible to read them by the previous barcode reading method and, to enhance the reading capability, the reading resolution of bars and spaces should be high. Previous barcode reading resolution is in a range of {fraction (3/1,000)}xcx9c{fraction (6/1,000)} inch, which is very difficult to obtain precise barcode reading.
This invention provides a system and a method of reading precise specification barcodes by sampling the acquired pulses through moving and scanning the reading objects, the printed 4-state barcodes or high-density barcodes, with a two-dimensional laser diode array.
A barcode reading system using a laser diode array of the present invention is provided. The barcode system includes barcode reading means, bar detecting means, information value calculating means, barcode reference table, and barcode information analyzing means.
The barcode reading means is for acquiring barcode information from a barcode image of an object by using a laser diode array. The bar detecting means is for recognizing a barcode type and detecting a beginning bar and an ending bar by using the acquired barcode information. The information value calculating means is for acquiring information of a black bar""s thickness and height values, and white bar""s space values from the beginning bar and the ending bar. The barcode reference table is for storing barcode analysis information in accordance with a barcode type. The barcode information analyzing means is for analyzing a barcode between the beginning bar and the ending bar by referencing the reference table in accordance with the barcode type.
Preferably, the barcode reading system of present invention further includes data sampling means. The data sampling means is for sampling the acquired barcode information by a laser diode unit and forwarding the sampled information to the bar detecting means.
More preferably, the barcode reading system further includes input means, driving means, moving beginning sensing means, and moving ending sensing means. The input means is for inputting a barcode reading beginning signal. The driving means is for moving the object into near the barcode reading means when the barcode reading beginning signal is inputted. The moving beginning sensing means is for sensing the object and generating a control signal to operate the barcode reading means when the object is approaching near the reading means. The moving ending sensing means is for sensing a moving ending of the object after the barcode information is read, and generating a control signal to end the operation of the barcode reading means.
Preferably, the laser diode array of the barcode reading means is 2xc3x978 or 4xc3x978 array.
A method for reading a barcode using a laser diode array of present invention is provided. The method includes the following steps. A barcode reading step is for acquiring barcode information from a barcode image of an object by using a laser diode array. A bar detecting step is for recognizing a barcode type and detecting a beginning bar and an ending bar by using the acquired barcode information. An information value calculating step is for acquiring information of a back bar""s thickness and height values, and white bar""s space values from the beginning bar and the ending bar. A barcode information analyzing step is for analyzing a barcode between the beginning bar and the ending bar by referencing a reference table in accordance with a barcode type, wherein the barcode reference table stores barcode analysis information in accordance with the barcode type.
Preferably, the method further includes a data sampling step. The data sampling step is for sampling the acquired barcode information by a laser diode unit and forwarding the sampled information to the bar detecting step.
More preferably, if the barcode type is a four-state barcode consisting of an ascender bar, a tracker bar and a full height bar, the barcode information analyzing step includes the following steps: A step for dividing the four-state bar into an upper area, a middle area, and a lower area; a step for obtaining a maximum value, a minimum value and an average value of the thickness of the black bar and the space value of the white bar, respectively; a step for obtaining a maximum value, a minimum value and an average value of the height value of the black bar; a step for dividing the barcode information by the character unit; and a step for applying the character unit barcode to the reference table to obtain the regarding information.
Preferably, the method further includes the following steps: A step for correcting an error by means of the check character included in the barcode information, and obtaining the regarding information by applying the reference table, if the error is occurred during the step of obtaining the regarding information; and a step for generating a regarding message and outputting the generated message, if the error is uncorrectable.
A computer readable recording media which records the computer program of present invention is provided. The program includes the following steps. The barcode reading step is for acquiring barcode information from a barcode image of an object by using a laser diode array. The bar detecting step is for recognizing a barcode type and detecting a beginning bar and an ending bar by using the acquired barcode information. The information value calculating step is for acquiring information of a back bar""s thickness and height values, and white bar""s space values from the beginning bar and the ending bar. And the barcode information analyzing step is for analyzing a barcode between the beginning bar and the ending bar by referencing a reference table in accordance with a barcode type, wherein the barcode reference table stores barcode analysis information in accordance with the barcode type.